<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    
    <script>

        let str = '张三'
        let  num = 456
        let bol = true
        let nu = null 
        let arr = []
// typeof  检测数据类型我的方式
        console.log(typeof str);

        console.log(typeof num);
        console.log(typeof cc);
        console.log(typeof bol);
        console.log(typeof str);
        console.loh(typeof )


    </script>
</body>
</html>